System for Collection of Chemical Spill

ABSTRACT

A collecting system for chemical spills is described, comprising an extended, protruding collector arm equipped with, at least, one pontoon ( 14 ) which is arranged to be pulled by a vessel, where the pollution floating on, or in, a water surface ( 50 ) is brought to flow along the pontoon ( 14 ) and to a collecting device ( 20 ) for collection of the chemical spill, and where the, at least, one pontoon ( 14 ) is equipped with a canvas ( 30, 30′ ) that lies around the pontoon ( 14 ). The canvas has a lower part ( 32, 32′ ) that extends out from the pontoon below the surface of water ( 50 ) to separate a surface layer of chemicals and water from the body of water lying underneath, and to lead the chemical to the collecting device ( 20 ), and a rope network ( 18 ) is connected to the canvas ( 30, 30′ ) to pull the canvas ( 30, 30′ ) and the pontoon ( 14 ) in the direction of travel.

The present invention relates to a collecting system for chemical spills comprising an extended, protruding collector arm equipped with, at least, one pontoon that is arranged to be pulled by a vessel, in which the pollution that floats on, or in, a water surface is brought to flow along the pontoon and to a collecting device for collection of the chemical spill, and where the, at least, one pontoon is equipped with a canvas that lies around the pontoon.

It is an object to provide a system for collection of chemicals in the form of oil after a discharge. The system is based on fishing technological solution models for fishing tools that are being towed and which today operate in nearly all kinds of weather, at least during weather conditions where oil is on the surface. The essence of these solutions is that forces are taken up and distributed through a framework of rope so that more sensitive parts of the construction, such as tarpaulins, are not stressed to the same extent. Modern rope networks have a strength which is considerably above that of stainless steel and can be used throughout the whole system.

Broadly, the system comprises one or two pontoons and a canvas surface that is set out from a drum and which is held extended next to a vessel with the help of a rope network fastened to the bow, and also a pump well fastened at the end of the pontoon(s) and which is towed with the help of a line from the bow of the vessel. For a 90 m vessel, one aims, for example, at a total width of the system of 50 m, but such a vessel can also operate two systems, one on either side of the vessel so that the total collecting width becomes 100 m. The canvas is held up by, and is surrounded by, one or two sausages (pontoons) of, for example, Hypalon covered polyester canvas. The oil is collected in that a horizontal, or near horizontal, planer-like edge or slit at the front of the canvas shaves the oil from the surface. The oil is then led along the pontoon and back to the pump well, where it is pumped to the vessel by a skimmer or a fish pump.

Of known patents, reference is made to NL 7705258 A and EP 0129279 A1, which both relate to a vessel with a collector arm that has a channel to lead oil towards a collection point. To lead the oil along a collector arm with the help of a rotating screw is known from US 2006/0201867 A1.

DE 3344597 A1 shows a collector arm in the form of a pontoon with an aeroplane wing shape, and where oil is led inside the pontoon.

Furthermore, U.S. Pat. No. 3,559,760 A and U.S. Pat. No. 4,673,497 A show the use of canvas bags for collection and storage, respectively, of oil. U.S. Pat. No. 3,612,280 A shows a vessel with extended, protruding collector arms, and U.S. Pat. No. 4,096,700 A shows an oil boom with up to two buoyancy bodies with a submersed canvas for collecting oil waste.

The present invention is considered for use in both oil spills from shipwrecks and other unintended discharges from vessels and for oil spills from oil installations for production and further transportation. The system is based on oil normally having a density (ca 0.8-0.9 g/cm³) which is less than that of seawater (ca 1.03 g/cm³), and consequently will lie on the surface as long as the weather conditions do not pull the oil below the surface through turbulence. However, the invention can be used for collection of all chemicals and also other viscous particulate materials that “float” in a corresponding way.

The system is generally asymmetrical in that it leads the oil from the outer edge and continuously backwards and inwards until the stream of oil ends up in a pump well with an open bottom so that water that follows the oil can exit through the bottom of the pump well, while the oil remains on the surface in the pump well and can be pumped onboard the vessel continuously.

The system can be self-spreading (for example, with an angle between about 30 and 60 degrees between the direction of travel and the pontoon) in that the liquid pressure along the collector arm forces it out from the side of the ship, at the same time as it is held in place by the towing resistance in the pontoon(s), and also by the pump well system that is suspended in a rope in the direction of travel.

It is an object of the present invention to provide a more efficient collecting system for chemicals such as oil, and which float on, or in, the surface of the water.

Said objects are obtained with a collecting system as described in the independent claim 1, in that the canvas has a lower part that protrudes out from the pontoon below the surface of the water to separate a surface layer of chemicals and water from the underneath-lying body of water and to lead the chemicals to the collecting device, and that a rope network is connected to the canvas to pull the canvas and the pontoon in the direction of travel.

Alternative embodiments are given in the dependent claims 2-12.

The canvas is preferably arranged around the pontoon in which the lower part can be shaped as a skirt that extends, in the main, horizontally out from the pontoon below the surface of the water, and an upper part of the canvas can, in the main, extend horizontally out from the pontoon above the surface of the water and be arranged to function as a splash screen.

The rope network or the lower part of the canvas can be equipped with lead weights arranged to regulate the draught of the canvas depending on the speed of towing.

The collector arm can, in a further embodiment, be equipped with a second pontoon, in which the second pontoon is arranged in front of said, at least, one pontoon.

The canvas can be arranged around both pontoons so that, at least, one partially closed space is formed between the pontoons, and the lower part of the canvas can be equipped with several slits to separate the surface layer of chemicals and water from the below-lying body of water.

The lower part of the canvas can, in an area between the slit openings and the pontoon, be equipped with lead weights or lead lines. Several outlets for surplus water can be arranged in an area adjoining the lead weight.

A number of straps can be arranged about one or both the pontoons, and be connected to the rope network. Furthermore, a number of straps or flat tape can run between the first and the second pontoon and be connected to the rope network.

A rear section of the lower part of the canvas can be fastened at the front of the rear pontoon, in an area mainly above the surface of the water. Furthermore, a canvas channel can be arranged below the pontoon, where the canvas channel is watertight at the rear and, at least, partially open at the front, and the canvas channel can be fastened at the front with flat bands to the lower part of the canvas.

The collecting device is preferably a pump well arranged to receive the chemicals and water that flow in along the collector arm and to pump the mainly chemical spill to the vessel or a towing bag.

In the latter case, water can be let out through a bottom outlet. It can also be preferred to lead the collector arms/pontoons directly into the towing bag, particularly for small systems adapted to small and basically equipped vessels.

The invention shall now be described in more detail with the help of the enclosed figures, in which:

FIG. 1 shows a principle diagram of a vessel equipped with a single collector arm according to the invention, and is shown without a canvas lying over it.

FIG. 2 shows a principle diagram of a vessel equipped with a single collector arm according to the invention, and is shown with a canvas lying over it.

FIG. 3 shows a principle diagram of a vessel equipped with a double collector arm according to the invention, and is shown without a canvas lying over it.

FIG. 4 shows a principle diagram of a vessel equipped with a double collector arm according to the invention, and is shown with a canvas lying over it.

FIG. 5 shows a section of a one pontoon solution according to the invention.

FIG. 6 shows a section of a two pontoon solution according to the invention.

FIG. 7 shows a further variant of the solution shown in FIG. 6.

FIG. 8 shows a section of a canvas area with slits.

FIG. 9 shows a suspension and rope fastening in front of a pontoon.

FIGS. 10 and 11 show a pump well, seen from above and the side, respectively.

As FIGS. 1, 2 and 5 show, a first embodiment of the present invention comprises a collector arm 10 that protrudes from the vessel 12 at an angle. The collector arm in this embodiment preferably comprises a pontoon 14 which is covered by a canvas 30. The canvas 30 can lie about the pontoon 14 such as shown in FIG. 5 so that the canvas lies round the pontoon with a U-shape. Furthermore, the canvas 30 is connected to a rope network 18 with several branches which are successively fastened in the longitudinal direction of the canvas.

The principle for collection of chemicals, such as oil, is that a lower part 32 of the canvas 30 forms a mainly horizontal canvas surface, such as a skirt, in front of the pontoon 14 and separates the surface layer of oil and water from the below-lying body of water. The surface of the water is shown with reference number 50. Water meets the pontoon 14 and is sent backwards and outwards, and the oil lies on top of this water layer and is brought backwards and in towards a pump well 20. The surplus water can flow out over the edge of the canvas, while the surface layer of oil flows backwards along the pontoon 14 and ends up in the pump well 20. Thus a “river” is formed along the pontoon 14 and the oil floats on top of this “river”. The horizontal canvas surface 32 is fastened at the front in the rope network 18 to the bow of the vessel 12. This rope network 18 pulls the canvas 30 and the pontoon 14 in the direction of travel. The ropes 18 a can be equipped with lead weights 42 just in front of the canvas 30, or alternatively, the lower parts 32 of the canvas can be equipped with lead plummets. This is to regulate the draught of the canvas in relation to the speed of towing, which can be, for example, between 3 and 5 knots.

As FIG. 5 shows, the upper part 34 of the canvas can extend correspondingly horizontally out from the pontoon 14 and above the surface of the water 50 so that a form of a splash screen is created. FIG. 2 shows the pontoon 14 with the upper canvas surface 34. The protrusion in front of the pontoon 14 can be equally long for both canvas surfaces 32, 34 so that an upper and a lower canvas edge are directly above each other, while the canvas 30 can be broader (for example, about 4 m) towards the pump well than at the outer end (for example, about 0.5 m).

FIGS. 3, 4 and 6 show a second variant of a collector arm (10′) with two pontoons 14, 16. The collector arm 10′ is correspondingly fastened in the rope network 18. The second variant is based on the same principle (surface oil is skimmed off together with water and forms a “river” back along the pontoon) but is somewhat differently formed. The front pontoon 16 can function as a wave dampener, at the same time as it positions several inlet slits 40 in the canvas 30′ at the correct depth to catch the oil on the surface, which can replace the lead weights on the ropes. The oil and a part of the water are forced under the forward pontoon 16 and through the slits 40 at the lower end 32′ of the canvas. In the gap between the pontoons 14, 16, the oil and water will form a river running backwards as in the first variant, and the surplus water can either be exit through the slits 44 at the rear of the gap between the pontoon, or flow out through the bottom of the pump well 20.

Shown in FIG. 6 is a first variant of the two pontoon solution. The canvas 30′ surrounds both the pontoons 14, 16 so that a mainly closed space is formed between the pontoons. The canvas 30′ is preferably fastened about the front pontoon 16 with several straps 36, and there can also be straps 38, 38′ running between the two pontoons 14, 16. As mentioned, the lower part 32′ is equipped with several slits 40 that extend in the longitudinal direction of the canvas. FIG. 8 shows an example of slits 40 in the lower part 32′ of the canvas 30′. The lower part 32′ of the canvas 30′ can be further equipped with lead weights or a lead line 42′ to regulate the position of the lower part 32′ in the water so that the slits 40 have the best possible effect in connection with the skimming off of the oil in the surface of the water.

The forward pontoon 16 can be surrounded by a net of fastening straps which in turn are fastened to the rope network 18, and can have fastening points for the rope network with gaps of 2-3 meters. The canvas 30′ surrounds both pontoons, and can have corresponding fastening points to the rope network with the forward pontoon.

In the application of the present principle the pontoons 14, 16 only need to be fastened to the flat straps 36 about the pontoon 16 with a few snap hooks 52 to be held in place. During operation, the water pressure will hold them where they shall be. The rope network 18 can also be fastened to the canvas with snap hooks. This makes it simple to replace components, and also to dismantle the equipment for cleaning. Each component becomes relatively light and small so that it can be handled relatively simply.

FIG. 7 shows a further variant of the two pontoon solution. The lower part 32′ of the canvas can be fastened at the front of the pontoon 14, which is shown with reference number 32 a. To help the distribution of power a channel 60 of canvas can be fitted under the pontoon 14 to provide more force transverse to the towing direction. This channel 60 can run in the whole length of the pontoon, under the middle of the pontoon and can be fastened with a flat band 64, for example, for every meter of the horizontal canvas part 32′ that collects the oil. The channel is watertight at the rear 62, and the channel can be held open in that it is weighted down underneath with a lead line threaded through a casing.

The pontoons 14, 16 can be held constant under a small overpressure (for example, 1.1 bar) via an air hose from an air outlet onboard or a compressor (not shown). This is simplified in that the asymmetric construction results in the rear part of the system always lying close to the aft part of the towing vessel 12.

The forces that work on the system (waves, currents, towing speed, towing resistance) are taken up through strong flat straps sewn/welded into the canvas surfaces.

The rope network can comprise rope of high molecular weight polyethylene (for example, Dyneema, Spectra) which is stronger than stainless steel of the same dimensions.

The pump well 20 (which can weigh about 1 ton) can be towed in the direction of travel in a separately dimensioned rope, for example, of Dyneema, where the rope can be fastened in its own rope bracket 80. The forces that affect the system do not affect the canvas surfaces or other weak parts of the construction, but are taken up via flat straps with large resistance to breaking and rope that can have overdimensioned resistance to breaking.

FIGS. 10 and 11 show the pump well in more detail. The pump well 20 can, in one embodiment example, be a well 72 in the form of, for example, a pipe with a diameter of 3 m and 1.5 m deep. The “river” along the pontoon 14 flows undisturbed straight into the pump well, and the water, which is heavier than the oil, is forced out through the open bottom 74, while the oil floats on the surface of the water and can be pumped onboard the towing vessel through a hose 54 via a hydraulic pump 76.

The pump well 20 inlet can comprise a horizontal slit 70 positioned under the water, preferably level with the horizontal lower part 32, 32′ of the canvas. The well 72 itself can be surrounded outside the inlet by a floating collar (not shown) that can be about 1 m tall and 1 m wide. The pump basin in the middle can be covered by a removable lid (not shown) which, together with the lower part 32, 32′ of the canvas, forms a closed space above the pump well pipe and the transition between the pontoon system and the pump well system. The pump well system can be made from aluminium and hollow spaces in the floating collar and the pontoon adapters can be filled with polyurethane foam.

An adapter can be screwed onto the system as a terminal for the other pontoon. The systems are otherwise alike. This means that one can swap between the two systems according to the weather conditions and oil type. In poor weather, the two pontoon system will be the better in that the waves are dampened and also the inlet depth is held constant. If the oil is thick (for example, heavy oil or heavily wax-containing oil types) the one pontoon system will probably be the better in that it will be possible to collect and pump clumps and the like.

The pump 76 can be a hydraulically driven pump, which can cope with about 90-130 l/m of hydraulic oil which can be delivered via a hose 82, withstand a maximum pressure of about 200 bar and can deliver 1600 tonnes water/hour at a height of about 5 m. The suction mouthpiece 78 of the pump can be placed about 10 cm below the liquid surface. Oil and water are pumped to the tank into the vessel 12, and the water is separated by gravity, and pumped onboard again.

If a vessel without tanks is used, the oil/water mixture can be pumped into towing bags of tarpaulin canvas surrounded by a network of flat straps which take up the forces (not shown). The towing bags can be filled by a hose from the pump in the pump well via a three-way valve on the aft deck of the vessel, and be put far into the bags. It is also possible to let the pontoons system end directly in the collecting bag if the system is used for small or poorly equipped vessels.

In the forward part of these bags there can be an outlet pipe stub on the underside where the water can flow out. The outlet pipe stub is a tarpaulin and can be closed from the vessel by tightening a line that is threaded through a casing at the end of the outlet pipe stub. When the bag is full of oil (the water is forced out through the outlet pipe stub) it can be released and anchored with an anchor line with a marker buoy. Before it is released a new bag is threaded into a parallel hose and the three-way valve directs the flow of liquid into this bag. Before the bag is released, it is closed by tightening a line threaded through a casing in the filling pipe stub and this filling pipe stub is weighed down so that it sinks under the bag and does not leak. The bag is held in position at the vessel by a line from the flat band network secured to a bollard. This can be fastened to the grapnel line and the buoy, which is released when the bag is full.

The systems are scalable and can be built for vessels from, for example, 10 m to 200 m. They do not require much towing power and a 10 m vessel with a motor power of about 100 HK can tow such a system at 4 knots. For vessels without available hydraulic power, a diesel driven hydraulic unit can be supplied. 

1. Collecting system for chemical spills comprising an extended, protruding collector arm equipped with, at least, one pontoon (14) which is arranged to be pulled by a vessel, in which pollution floating on or in a water surface (50) is brought to flow along the pontoon (14) and to a collection device (20) for collection of the chemical spill, and where the, at least, one pontoon (14) is equipped with a canvas (30, 30′) that lies around the pontoon (14), wherein the canvas has a lower part (32, 32′) that extends out from the pontoon below the surface of water (50) to separate a surface layer of chemicals and water from the underlying body of water, and to lead the chemicals to the collecting device (20), and that a rope network (18) is connected to the canvas (30, 30′) to pull the canvas (30, 30′) and the pontoon (14) in the direction of travel.
 2. System according to claim 1, wherein the canvas (30) is arranged around the pontoon (14), in which the lower part (32) is formed as a skirt that extends mainly horizontally out under the surface of water (50), and that an upper part (34) of the canvas extends mainly horizontally out from the pontoon above the surface of water (50) and is arranged to function as a splash screen.
 3. System according to claim 1, wherein the rope network (18) or the lower part (32) of the canvas (30) is equipped with lead weights (42) arranged to regulate the draught of the canvas (30) depending on the speed of towing.
 4. System according to claim 1, wherein the collector arm (10) is equipped with a second pontoon (16) where the second pontoon (16) is arranged in front of the, at least, one pontoon (14).
 5. System according to claim 4, wherein the canvas (30′) is arranged around both pontoons (14, 16) so that, at least, a partial enclosed space is formed between the pontoons and that the lower part (32) of the canvas is equipped with several slits (40) to separate the surface layer of chemicals and water from the body of water lying below.
 6. System according to claim 5, wherein the lower part (32′) of the canvas, is equipped with lead weights (42′) in an area between the slits (40) and the pontoon (14).
 7. System according to claim 6, wherein several outlets (44) for surplus water are arranged in an area adjoining the lead weight (42′).
 8. System according to claim 5, wherein a number of straps (36) are arranged around one or both pontoons (14, 16) and which are connected to the rope network (18).
 9. System according to claim 5, wherein a number of straps (38, 38′) that are connected to the rope network (18) run between the first and the second pontoon (14, 16).
 10. System according to claim 2, wherein a rear part (32 a) of the lower part (32′) of the canvas is fastened in front of the rear pontoon (14), in an area above the water surface (50).
 11. System according to claim 10, wherein a canvas channel (60) is arranged below the pontoon (14), where the canvas channel (60) is watertight at the rear edge (62) and, at least, partially open at the front (64), and that the canvas channel (60) is fastened at the front (64) to the lower part (32′).
 12. System according to claim 1, wherein the collecting device is a pump well (20) arranged to receive chemicals and water that flow along inwards along the collector arm (10), and to pump, in the main, chemicals to the vessel or a towing bag.
 13. System according to claim 5, wherein a rear part (32 a) of the lower part (32′) of the canvas is fastened in front of the rear pontoon (14), in an area above the water surface (50).
 14. System according to claim 13, wherein a canvas channel (60) is arranged below the pontoon (14), where the canvas channel (60) is watertight at the rear edge (62) and at least, partially open at the front (64), and that the canvas channel (60) is fastened at the front (64) to the lower part (32′). 